1. Field of the Invention
The present invention relates to an apparatus for exercising the abdominal and other muscles associated with full flexure of the lower spine.
2. Description of the Prior Art
Proper exercising of the abdominal muscles to obtain maximal results is a concern Of a large number of fitness enthusiasts; yet the mechanics of proper exercising are rarely fully understood. The present invention eliminates the need for an exercising individual to understand muscle mechanics in order to maximize exercising effects.
Muscles are obviously intended to cause motion of a skeletal frame. Therefore, exercise is naturally limited by the ability of the bones of joint to move through the joint's maximal range of motion. Conversely, to maximize the exercise of all groups of muscles associated with a joint, the bones must be taken through their entire range of motion. If not fully utilized, muscle groups may be entirely unused or ineffectively exercised.
This concept is particularly evident when examining the mechanics of the human spine, which has a maximal total range of motion of approximately forty degrees when the lumbar and thoracic spine are flexed forward. Thirty degrees of this motion is accomplished by the lower spine associated with the lordotic curvature, commonly referred to as "the small of the back". Unless the spine is flexed through its entire range of motion at the proper spot in the spine, the abdominal muscle groups needed to flex the spine are incompletely utilized.
Therefore, the present invention provides a means by which abdominal muscles are exercised by forcing the small of the back against a resistive platform, thereby forcing the spine to flex from a normal resting lordotic curvature through the maximal forward flexure of the spine. Although numerous inventions are ergonomically designed, none found in the prior art use means similar in concept to the present invention to exercise abdominal muscles.
For example, U.S. Pat. No. 2,264,046 issued Nov. 25, 1941 to McClellan describes an exercising platform supported on a solid surface, which is centrally hinged, and having ankle shackles. An adjustable bolster attaches to the platform, intended to fit below the arch of the user's back, over which the user arches exerting force against the ahkle shackles to accomplish a sit-up like maneuver. The bolster only causes a change in the relative amount of body weight which the abdominal muscles must resist to perform a sit-up, and fails to direct the user's efforts at flexing the spine to direct a force through the bolster.
U.S. Pat. No. 5,099,831 issued Mar. 31, 1992 to Freed describes a posture improving device by providing thoracic extension. A flexible membrane in the thoracic area connected by a cable and pulley system to arm rests is projected upward into the thoracic spine stretching certain muscles. Posterior forces must be applied by the arms to the rests to cause the membrane to project into the spine, unlike the operation of the present invention.
Other ergonomic exercise devices seen in the prior art entirely fail to provide resistance mechanisms for exercise of the muscles flexing the spine. U.S. Pat. No. 5,205,804 issued Apr. 27, 1993 to Hall teaches a method for strengthening lower back muscles including positioning the user on a platform having an ankle engaging element and a protrusion over which the user supports the user's pelvis. This apparatus must be used in a prone position and is thus inappropriate for use as a resistive mechanism against the lower spine. U.S. Pat. No. 4,307,880 issued Dec. 29, 1981 to Abram describes a device made up of a elongated resiliently deformable element movable to a position in which it assumes a concave contour and is fixedly retained, so that, when a user reclines therein, a bow-like posture is assumed, assisting the user to learn Yoga positions.
U.S. Pat. No. 4,489,936 issued Dec. 25, 1984 to Dal Monte describes a rigid board for receiving the user's body in various positions and an adjustable lever and fulcrum mechanism attached under the board, whereby the user selectively levers the board with his arms or legs to rock it, utilizing his own weight as a resistive element against the levering action. U.S. Pat. No. 5,232,426 issued Aug. 3, 1993 to Van Straaten describes an exercising machine having support legs and hinged platform movable between an operative state in which the legs define a support stand adjustable to various stationary inclinations and an inoperative collapsed state.
Hinged platforms for various uses are also found in the prior art. German publication No. 0 208 208 published Jan. 1, 1987 by inventor Heinz Kett er describes a training bench with an adjustable backrest for use in weight training. British Patent Application No. 2 192 343 by inventors Mahnke and Sheltra published Jan. 13, 1988 also describes a training bench with an adjustable backrest. U.S. Pat. No. 4,207,635 issued Jun. 17, 1980 to Leroy describes a rest surface which is flat and adapted to receive the body in stretched out position. It is a reversible mat having a swell which, when laid upon in a prone position, causes a kyphosis of the spine in the region of the lumbar vertebrae. None of these devices provide a resistance means to application of force by the lower back.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.